JF-A-59764/1981 discloses (3,4-diarylisoxazol-5-yl)acetic acid derivatives as a compound having anti-inflammatory, analgesic and antipyretic activities. The processes thereof are known in (1) the above publication and (2) JP-A-75471/1985.
JP-A-59764/1981 ##STR3## wherein R.sup.1 and R.sup.2 are as defined above.
The above contemplated compound is obtained by reacting 3,4-diaryl-5-methylisoxazole with n-butyl lithium in tetrahydrofuran while cooling by use of dry ice-acetone mixture, pouring the reaction mixture into pulverized dry ice, and then treating the mixture with acid.
JP-A-75471/1985 ##STR4## wherein X is halogen atom, R.sup.1 and R.sup.2 are as defined above. This process comprises reacting 3,4-diaryl-5-methylisoxazole with a halogenating agent and then with a cyanogenation agent to obtain 3,4-diaryl-5-cyanomethylisoxazole, and subjecting the same to solvolysis.
The present inventors have investigated an industrial process for preparing (3,4-diarylisoxazol-5-yl)acetic acid derivatives and found the methods disclosed in (1) and (2) have various problems. In the method (1), the reagent, n-butyl lithium, is liable to ignite and causes problems in fire and safety when used in a large quantity. Further, this method comprises problems in process efficiency including operation efficiency, because dry ice having high hygroscopicity is used in the reaction which requires anhydrous reaction condition and low temperature -70.degree.C. The method (2) is more complicate than the method (1), and is not a preferable industrial process in view of safety due to the use of cyano compound.
An object of the present invention is to provide novel .alpha.,.beta.-unsaturated ketone and ketoxime derivatives useful as intermediates for preparing the compound (A) by a simple process which uses no dangerous reagent and is excellent in safety and operation efficiency.